Recently, digital copying machines and network copying machines have advanced. Various printing functions are also proposed, and a plurality of pages contained in a single document or a plurality of documents can be laid out and printed on one paper sheet.
For example, materials often distributed at a meeting and the like are merely a reference, and in many cases, an N-page document is laid out and printed on one paper sheet such that two or four pages of one document are laid out and printed on one paper sheet (to be referred to as N-page printing hereinafter). When the pages of documents must be referred to at once, they are sometimes coupled and printed (to be referred to as coupled printing hereinafter). Further, page numbers may be printed in an order of bookbinding so as to fold a document into two after printing (to be referred to as bookbinding printing hereinafter).
Printing of laying out an N-page document and printing it on one paper sheet, such as N-page printing, coupled printing, and bookbinding printing, will be called Nup printing.
There is proposed a system capable of reading a paper document by a scanner, retrieving original electronic data of the read paper document image, and printing the image from the original electronic data itself, distributing the original electronic data to a desired terminal such as a PC (Personal Computer) within a network, saving it in a desired storage medium within a network, or editing it.
As a method for realizing this, for example, in Japanese Patent No. 3017851, original electronic data of scanned electronic data can be retrieved by comparing bit by bit the scanned electronic data obtained by scanning a paper document and electronic data in a storage medium.
For example, in Japanese Patent Laid-Open No. 2001-257862, when a paper document is to be converted into electronic data, an identification code is added to the electronic data to generate a printed material containing the identification code. To retrieve or print electronic data corresponding to the printed material, the printed material is loaded to recognize the printed identification code, thereby retrieving or printing desired electronic data.
However, the above references do not consider any Nup-printed document, and the following problems arise in an environment where Nup printing is adopted.
For example, in Japanese Patent No. 3017851, electronic data obtained by scanning an Nup-printed document is interpreted as one page. To the contrary, original electronic data is managed for each page in a storage medium, and thus no high similarity can be obtained by a comparison with any electronic data. Thus, no original electronic data can be retrieved.
For example, in Japanese Patent Laid-Open. No. 2001-257862, the print position of an identification code on each page is determined. In Nup printing, the print position shifts, and each identification code cannot be read. As a result, no original electronic data can be retrieved.